Light detection and ranging (LIDAR) operates in a manner similar to that of RADAR, but utilizes laser light instead of microwaves. In a LIDAR system, a laser beam may be directed to an object or a group of objects, which could include molecules or particles in the atmosphere. Light reflected or backscattered from the objects may be received and analyzed to determine distance, direction, and/or speed of the objects.
Some of the challenges involved with LIDAR include very weak reflected or backscattered signals that are available for detection. Other challenges stem from non-ideal behavior of optical components. For example, when multiple etalons are used for filtering a LIDAR system, relative spectral drifts and non-identical spectral transmission functions associated with multiple independent optical filters can limit the accuracy and/or the sensitivity of the measurement.